Research goals for the coming year are as follows: 1. Development of Affinity Chromatographic Column(s) for Scaled up Purification of Pancreatic Cholesterol Esterase. This procedure will depend upon selective adsorption of cholesterol esterase to an affinity column prepared with anti-cholesterol esterase IgG or upon immunosubtraction where the labile cholesterol esterase passes through the affinity column while the undesired proteins are bound. Selective adsorption will be employed if cholesterol esterase can be eluted from the antibody with retention of enzymatic activity. 2. Intra-Cellular Localization of Mucosal Cholesterol Esterase. The localization studies already in progress will be extended to electron microscopy. The indirect peroxidase-labeled antibody technique will be employed. Conditions for the light microscopy studies will be altered to reduce the deposition of non-specific reaction product in control tissues. 3. Investigation of Factors Which Influence the Synthesis and Transport of Lipoproteins from the Intestinal Cell Model. Initial studies will be designed to identify the nature of the stimulatory effect of plasma on lipid release. Apo C, which is present in lymph lipoproteins but not synthesized in intestine, may be the component of plasma which stimulated lipid release. 4. Cholic Acid Analogues Coupled to Non-Absorbable Carriers as Inhibitors of Cholesterol Esterase and Cholesterol Absorption. Cholic acid analogues induce aggregation of cholesterol esterase subunits into an inactive cholesterol esterase. A non-absorbable carrier with a side arm that can be coupled to the bile acid analogue will be selected and the cholic acid analogue will be linked to this through a covalent bond. 5. Investigation of the Effect of Non-Nutritive Fiber on Cholesterol Absorption. Fibers will be screened in vitro for their ability to bind cholesterol, bile acids and cholesterol esterase.